While full courses are available through a choice of subscription plans, you can view free sample lessons for each of the courses to get an idea of what they’re like and to view information about the teachers.

A main benefit I see from the way the site is set up is that a subscription provides not just access to one course, but to all of them. In addition, the courses are broken up into short topics, so you can use them in their entirety, or choose only the parts you want to view.